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A tidal freshwater
marsh along the upper Cape Fear River estuary, near
Wilmington, NC |
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Bull-tongue Arrowhead
(Sagittaria lancifolia). Arrowheads can not
survive in salty water. They are common in the freshwater marshes in the upper reaches of
the estuary. |
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Pickerelweed (Pontedaria
cordata) has showy purple flowers that bloom in
the early summer. It is another plant commonly found in
North Carolina tidal freshwater marshes. |
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Soft Rush (Juncus
effusus) is a rush, like Black Needlerush (Juncus
roemerianus). But it can not survive in salty
water. While Black Needlerush grows in salt and
brackish marshes, Soft Rush is only found in freshwater
marshes. Waterlilies (Nyphae
species) are also common in the tidal freshwater zone. |
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A tidal swamp forest in Brunswick
County, NC |
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Tidal Freshwater Marsh
Tidal freshwater marshes are found in the upper part
of estuaries.
This far from the sea, there is little or no salt in the water.
These marshes may be flooded by tides every day or they may only
flood every once in a while. The tides bring
nutrients and
sediment
from the ocean into the marshes. This makes tidal
freshwater marshes very good places for plants to grow. Tidal
freshwater marshes are a lot like salt marshes, but without the
salt. Many more kinds of plants can grow in tidal
freshwater marshes because the water is not salty.
The plants that grow in tidal freshwater marshes
changes throughout the year. In the winter, the marsh has
only bare mud. In the spring, fleshy broad-leaved plants such as arrowheads
begin to grow. In the summer, these plants are replaced by
grasses and grass-like plants. Some of the plants found in
these marshes are Giant Cordgrass (Spartina cynosuroides), Sawgrass (Cladium
jamaicense), Cattails (Typha species), Arrow Arum (Peltandra virginica),
Pickerelweed (Pontedaria cordata), and Blue Flag (Iris
virginica).
More birds use tidal freshwater marshes for feeding,
nesting, and breeding, than any other type of marsh.
Tidal freshwater marshes are important for both freshwater and
salt water organisms. Freshwater fish feed in these
marshes. Many
estuarine
and
marine
species use them as
nursery
habitat .
Tidal Swamps
Tidal swamps grow around freshwater sounds and
along the
mouths of both
blackwater
and brownwater
rivers. They grow far up the estuary, where salt water
does not reach. Tides bring fresh water into and out of
the water each day.
Because the trees can not stand salt, major storms
like hurricanes can cause a lot of damage. The trees can
usually survive being flooded with salt water every once in a
while. But, if storms bring salt into the swamp too often, it can
kill the trees. Then, the swamp will be replaced
by marsh.
Tidal swamps have many of the same trees as
riverine swamps. Some of the trees that grow in tidal
swamps are Bald Cypress (Taxodium distichum),
Water tupelo (Nyssa aquatica), and Swamp tupelo (Nyssa
biflora).
Click on the bird to continue... |
